1. Field of the Invention
The present invention relates to a zoom lens and an imaging apparatus, and particularly relates to a zoom lens which is compact and has a wide field angle so as to be suitably applied to imaging optical systems of digital input/output equipment such as digital video cameras, digital still cameras and the like, as well has having high optical performance, and to an imaging apparatus using this zoom lens.
2. Description of the Related Art
Imaging apparatuses such as digital still cameras, which use solid-state imaging devices, are coming into widespread use. Demand is increasing for even higher image quality with these imaging apparatuses such as digital still cameras. Particularly, with digital still cameras, there is demand for imaging lenses, zoom lens in particular, having excellent imaging performance capable of handling solid-state imaging devices with a great number of pixels.
There is also strong demand for wider field angles as of recent, in addition to the above, such as compact zoom lenses having a high zoom factor and a wide field angle exceeding 38° for the half-angle.
While there are many types of zoom lenses for digital still cameras, including a three-group zoom lens which is suitably used with compact and wide-angle applications. This three-group zoom lens is configured of a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power, in order from the object side. Examples of this three-group zoom lens can be found in Japanese Unexamined Patent Application Publication Nos. 2004-13169, 2006-113554, 2007-212636, and 2007-140359. The arrangement described in Japanese Unexamined Patent Application Publication Nos. 2004-13169 and 2006-113554 realizes a wide angle by configuring the first lens group of three lenses. The arrangement described in Japanese Unexamined Patent Application Publication Nos. 2007-21263.6 and 2007-140359 realizes reduction in size by configuring the first lens group of two lenses.